Method and system for governing an engine in low power

Abstract

The present invention relates to methods and systems for managing engines in a low power state. Methods and systems for operating an aircraft having two or more engines are described. One method includes operating the two or more engines of the aircraft in an asymmetric operating regime, wherein a first one of the engines is in an active mode to provide power to the aircraft and a second one of the engines is in a standby mode to provide substantially no power to the aircraft; managing the first engine in the active mode using first management logic; and managing the second engine in the standby mode using second management logic, the second management logic based on a target compressor speed adjusted using a trim value and a variable geometry mechanism (VGM) setting, the trim value dependent on at least one parameter of the second engine in the standby mode.

Description

Technical Field

[0001] This disclosure relates generally to engine control, and more specifically to engine control logic for engines operating at low power. Background Technology

[0002] When operating an aircraft with multiple engines, certain parts of the mission may not require both engines to operate at full power. Operating a single engine at relatively high power during cruise conditions, rather than multiple engines at lower power, can achieve better fuel efficiency. For example, one or more engines may operate at high power, while one or more of the remaining engines operate in a mode sometimes referred to as "standby." However, engine management can be challenging at certain power / rated settings.

[0003] Therefore, the solution needs to be improved. Summary of the Invention

[0004] In one aspect, a method for operating an aircraft having two or more engines is provided. The method includes: operating the two or more engines of the aircraft using an asymmetric operating mechanism, wherein a first engine of the engines is in an active mode to power the aircraft, and a second engine of the engines is in a standby mode to substantially not power the aircraft; controlling the first engine in the active mode using first control logic; and controlling the second engine in the standby mode using second control logic based on a target compressor speed and variable geometry (VGM) setting adjusted using a trim value, the trim value depending on at least one parameter of the second engine in the standby mode.

[0005] In another aspect, a method for operating a gas turbine engine is provided. The method includes: obtaining a target compressor speed and variable geometry (VGM) setting adjusted using trimmed values, the trimmed values ​​depending on at least one parameter of an engine operating in a given operating mode; determining an error between the adjusted target compressor speed and the actual compressor speed of the engine; and adjusting the fuel flow rate to the engine based on the error when the engine is in the given operating mode.

[0006] On the other hand, a system for operating an aircraft having two or more engines is provided. The system includes at least one processing unit and a non-transitory computer-readable medium thereon storing program code. The program code is executable by the processing unit to: operate the two or more engines of the aircraft in an asymmetric operating mechanism, wherein a first engine of the engines is in an active mode to provide power to the aircraft, and a second engine of the engines is in a standby mode to substantially not provide power to the aircraft; manage the first engine in the active mode using first control logic; and manage the second engine in the standby mode using second control logic, the second control logic being based on a target compressor speed and variable geometry (VGM) setting adjusted using trim values, the trim values ​​depending on at least one parameter of the second engine in the standby mode. Attached Figure Description

[0007] Now refer to the attached diagram, in which:

[0008] Figure 1A It is a schematic cross-sectional view of a multi-engine aircraft;

[0009] Figure 1B It is used for Figure 1A A schematic diagram of an exemplary multi-engine system for an aircraft, showing an axial cross-sectional view of two gas turbine engines;

[0010] Figure 2 It is used for Figure 1A Multi-engine aircraft Figure 1B A schematic axial cross-sectional view of one of the gas turbine engines;

[0011] Figure 3 This is a block diagram of an exemplary implementation of an engine controller;

[0012] Figures 4A-4B These are exemplary embodiments of the first control logic and the second control logic, respectively.

[0013] Figures 5A-5C This is a diagram illustrating the application of trimming to engine parameters;

[0014] Figure 6 It is a block diagram of an exemplary computing device; and

[0015] Figure 7 This is a flowchart of a method for operating an aircraft with two or more engines. Detailed Implementation

[0016] This article describes methods and systems for controlling the engines in an aircraft with two or more engines. In certain situations, it may be desirable to operate the aircraft using a so-called “asymmetric operating regime” (AOR), which is described in more detail below. When operating in AOR, multiple engines of a multi-engine helicopter or other rotorcraft can be operated at different output power levels.

[0017] Figure 1A An exemplary multi-engine aircraft 100 is depicted, which in this case is a helicopter. The aircraft 100 includes at least two gas turbine engines 102, 104. In the depicted helicopter application, these two engines 102, 104 can be interconnected via a common gearbox to form a multi-engine system 105, such as... Figure 1B As shown, the multi-engine system 105 drives the main rotor 108.

[0018] Now go to Figure 1B The illustration depicts an exemplary multi-engine system 105, which can be used as a power plant for an aircraft, including but not limited to a rotorcraft such as a helicopter 100. The multi-engine system 105 may include two or more gas turbine engines 102, 104. In the case of a helicopter application, these gas turbine engines 102, 104 will be turboshaft engines. Control of the multi-engine system 105 is achieved through one or more controllers 210, which may be a full-authority digital engine control (FADEC), an electronic engine controller (EEC), etc., as described below, and are programmed to manage the operation of the engines 102, 104 to reduce overall fuel consumption, particularly during sustained cruise operation mechanisms, where the aircraft operates at a sustained (steady-state) cruise speed and altitude. This cruise operation mechanism is typically associated with the operation of existing technology engines at equivalent partial power, such that each engine contributes approximately equally to the output power of the system 105. Other phases of a typical helicopter mission include transient phases such as takeoff, climb, stationary flight (hovering), approach, and landing. Cruises may occur at higher altitudes and speeds, or at lower altitudes and speeds, such as during the search phase of a search and rescue mission.

[0019] More specifically, the multi-engine system 105 of this embodiment includes first and second turboshaft engines 102, 104, each having a corresponding transmission 152 interconnected via a common output gearbox 150 to drive a common load 170. In one embodiment, the common load 170 may include the rotor of a rotorcraft. For example, the common load 170 may be the main rotor 108 of aircraft 100. Depending on the type of the common load 170 and its operating speed, each of the turboshaft engines 102, 104 may be drivably coupled to the common load 170 via the output gearbox 150, which may be of a reduction type.

[0020] For example, gearbox 150 may have multiple drive shafts 156 to receive mechanical energy from respective output shafts 154 of the respective turboshaft engines 102, 104. Gearbox 150 may be configured to direct at least some of the combined mechanical energy from the plurality of turboshaft engines 102, 104 to a common output shaft 158 ​​to drive a common load 170 at a suitable operating (e.g., rotational) speed. It is to be understood that the multi-engine system 105 may also be configured, for example, to drive accessories and / or other components of the associated aircraft. As will be described, gearbox 150 may be configured to allow the common load 170 to be driven by any one of the turboshaft engines 102, 104, or by a combination of two engines 102, 104.

[0021] In this disclosure, although the aircraft conditions (cruise speed and altitude) are substantially stable, the engines 102 and 104 of system 105 can be operated asymmetrically, with one engine operating in a high-power "active" mode and the other engine operating in a low-power (which in some cases may be no power) "standby" mode. This provides the aircraft with an opportunity to save fuel, but there may also be other suitable reasons for desiring asymmetrical engine operation. Therefore, this operational management may be referred to as "asymmetric mode" or the aforementioned AOR, in which one of the two engines operates in a low-power (which in some cases may be no power) "standby" mode while the other engine operates in a high-power "active" mode. Such asymmetric operation can be performed for the cruise phase of flight (continuous, steady-state flight, which is typically at a given commanded constant aircraft cruise speed and altitude). The multi-engine system 105 can be used in aircraft such as helicopter 100, but also has applications in suitable marine and / or industrial applications or other ground operations.

[0022] Still referencing Figure 1BAccording to this disclosure, in this example, a multi-engine system 105 drives an AOR-operable helicopter 100, wherein the first of the turboshaft engines (e.g., 102) can operate at high power in an active mode, and the second of the turboshaft engines (104 in this example) can operate in a low-power (which may in some cases be no power) standby mode. In one example, the first turboshaft engine 102 can be controlled by controller 210 to operate at full (or near full) power in an active mode to supply substantially all or all of the required power and / or speed requirements of the common load 170. The second turboshaft engine 104 can be controlled by controller 210 to operate in a lower power or no-output power state to substantially not supply or not supply the required power and / or speed requirements of the common load 170. Optionally, a clutch can be configured to disengage the low-power engine.

[0023] Controller 210 can control the engine's power management according to appropriate planning or control mechanisms, as will be described in more detail below. Controller 210 may include a first controller for controlling the first engine 102 and a second controller for controlling the second engine 104. The first and second controllers can communicate with each other to implement the operations described herein. In some embodiments, a single controller 210 may be used to control both the first engine 102 and the second engine 104.

[0024] In another example, the engine's AOR can be achieved through differential control of the fuel flow to the engine by one or more controllers 210, as described in U.S. Patent Application Publication No. 2020 / 0049025, the entire contents of which are incorporated herein by reference. In some examples, low fuel flow may also include zero fuel flow.

[0025] While various differential controls between the engines of engine system 105 are possible, in one particular embodiment, controller 210 may correspondingly control the fuel flow rate to each engine 102, 104. In the case of a standby engine, the fuel flow rate (and / or fuel flow rate) supplied to the standby engine may be controlled to be between 70% and 99.5% less than the fuel flow rate (and / or fuel flow rate) supplied to the active engine. In an AOR (Automatic Response) configuration, the standby engine may be maintained to have a fuel flow rate between 70% and 99.5% less than the active engine. In some embodiments, the fuel flow rate difference between the active and standby engines may be controlled to be within 70% to 90% of each other, wherein the fuel flow rate to the standby engine is 70% to 90% less than that to the active engine. In some embodiments, the fuel flow rate difference may be controlled to be within 80% to 90%, wherein the fuel flow rate to the standby engine is 80% to 90% less than that to the active engine.

[0026] In another embodiment, controller 210 may operate one engine (e.g., 104) of the multi-engine system 105 at a power significantly lower than the engine's rated cruise power level in standby mode, and in some embodiments at substantially zero output power, and in other embodiments at less than 10% of the output power relative to a reference power (provided at a reference fuel flow rate). Alternatively, in some embodiments, controller 210 may control the standby engine to operate at a power range of 0% to 1% of the standby engine's rated full power (i.e., when the second engine operates in standby mode, the power output of the second engine to the common gearbox is maintained between 0% and 1% of the second engine's rated full power).

[0027] In another example, Figure 1B The engine system 105 can operate in AOR mode by controlling the relative speed of the engines using controller 210; that is, the idle engine is controlled at a target low speed, and the active engine is controlled at a target high speed. For example, such low-speed operation of the idle engine may include a rotational speed less than the engine's typical ground idling speed (i.e., "sub-idling" engine speed). Other control mechanisms can be used to operate the engine in AOR mode, such as control based on a target pressure ratio or other suitable control parameters.

[0028] Although the example described herein illustrates two engines, AOR applies to more than two engines, whereby at least one of the engines operates in a low-power standby mode while the remaining engines operate in an active mode to supply all or substantially all of the required power and / or speed demands of the common load.

[0029] In operation, the first turboshaft engine (e.g., 102) can operate in active mode, while the other turboshaft engine (e.g., 104) can operate in standby mode, as described above. During AOR operation, if the helicopter 100 requires an increase in power (expected or otherwise), the second turboshaft engine 104 may need to provide more power relative to the low-power standby state and may immediately return to a high-power or full-power state. For example, this could occur in an emergency situation of the multi-engine system 105 that powers the helicopter 100, where the "active" engine loses power, and power recovery from low to high power may take some time. Even without an emergency, it would be expected to re-energize the standby engine to exit AOR.

[0030] refer to Figure 2Turboshaft engines 102 and 104 can be implemented as gas turbine engines. Although the foregoing discussion relates to engine 104, it should be understood that engine 102 can be substantially similar to engine 104. In this example, engine 104 is a turboshaft engine, which typically includes the following components in series communication: a low-pressure (LP) compressor section 12 and a high-pressure (HP) compressor section 14 for pressurizing air; a combustor 16 in which compressed air is mixed with fuel and ignited to produce an annular flow of hot combustion gases; a high-pressure turbine section 18 for extracting energy from the combustion gases and driving the high-pressure compressor section 14; and a low-pressure turbine section 20 for further extracting energy from the combustion gases and driving at least the low-pressure compressor section 12.

[0031] The low-pressure compressor section 12 can rotate independently of the high-pressure compressor section 14. The low-pressure compressor section 12 may include one or more compression stages, and the high-pressure compressor section 14 may include one or more compression stages. A compressor stage may include a compressor rotor, or a combination of a compressor rotor and a compressor stator assembly. In a multi-stage compressor configuration, the compressor stator assembly guides air from one compressor rotor to the next.

[0032] Engine 104 has multiple, i.e., two or more spools that perform compression to pressurize air received through air inlet 22 and extract energy from combustion gases before they leave via exhaust outlet 24. In the illustrated embodiment, engine 104 includes a low-pressure spool 26 and a high-pressure spool 28 mounted for rotation about engine axis 30. The low-pressure spool 26 and the high-pressure spool 28 are rotatable about axis 30 independently of each other. The term "spool" is intended herein to broadly refer to the drive-connected turbine and compressor rotor.

[0033] The low-pressure pipe shaft 26 includes a low-pressure shaft 32 that interconnects the low-pressure turbine section 20 with the low-pressure compressor section 12 to drive the rotor of the low-pressure compressor section 12. In other words, the low-pressure compressor section 12 may include at least one low-pressure compressor rotor directly coupled to the low-pressure shaft 32, and the low-pressure turbine section 20 may include at least one low-pressure turbine rotor directly coupled to the low-pressure shaft 32 to rotate the low-pressure compressor section 12 at a speed proportional to the speed of the low-pressure turbine section 20. The high-pressure pipe shaft 28 includes a high-pressure shaft 34 that interconnects the high-pressure turbine section 18 with the high-pressure compressor section 14 to drive the rotor of the high-pressure compressor section 14. In other words, the high-pressure compressor section 14 may include at least one high-pressure compressor rotor directly coupled to the high-pressure shaft 34, and the high-pressure turbine section 18 may include at least one high-pressure turbine rotor directly coupled to the high-pressure shaft 34 to rotate the high-pressure compressor section 14 at the same speed as the high-pressure turbine section 18. In some embodiments, the high-pressure shaft 34 may be hollow, and the low-pressure shaft 32 extends through it. The two shafts 32, 34 can rotate freely independently of each other.

[0034] The engine 104 may include a transmission 38 driven by a low-pressure shaft 32 and driving a rotatable output shaft 40. The transmission 38 may change the ratio between the rotational speeds of the low-pressure shaft 32 and the output shaft 40.

[0035] Engine 104 includes one or more variable geometry mechanisms (VGMs), such as inlet guide vanes (IGVs) 42, which are movable to direct air into compressor section 12 (e.g., compressor inlet guide vanes). For example, IGV 42 may include low-pressure compressor inlet guide vanes, medium-pressure compressor inlet guide vanes, and / or high-pressure compressor inlet guide vanes. However, it should be understood that in some embodiments, VGMs may consist of outlet guide vanes for directing air outward from compressor section 12, variable stator vanes for directing incoming air into rotor blades of engine 104, variable nozzles, treatment vent valves, etc.

[0036] As described above, control of the operation of engine 104 can be achieved through one or more control systems, such as controller 210. Controller 210 can regulate the fuel flow rate (W) supplied to engine 104. fThe controller 210 can control the operation of multiple engines, such as engines 102 and 104. For example, the controller 210 may be equipped with one or more FADECs or similar devices. Each FADEC may be assigned to control the operation of one or more of engines 102 and 104. Additionally, in some embodiments, the controller 210 may be configured to control the operation of other components of the aircraft 100, such as the main rotor 108.

[0037] In some embodiments, controller 210 is configured to use control logic to manage engine 104 operating in standby mode, which differs from the control logic used at higher rated power. For example, some control logic based on fuel flow can be challenging in standby mode because the inaccuracy of fuel flow commanded by the engine increases at low fuel flow rates. Additionally, control logic based on compressor or output shaft speed may result in variations between different engines at low speeds. Therefore, this document describes control logic suitable for managing an engine operating in standby mode.

[0038] refer to Figure 3 The controller 210 includes an operation mode selector 304 that determines the operation mode of engines 102, 104 in response to pilot input 302. For example, pilot input 302 may cause engines 102, 104 to operate in AOR or any other operation mechanism, where different control logics are suitable for engines 102, 104. The operation mode selector 304 then causes the two engines 102, 104 to be controlled using the corresponding logic for each respective operation mode. More specifically, engine 102 operating in active mode is controlled by engine control logic 306 according to a first control logic, and engine 104 operating in standby mode is controlled by engine control logic 308 according to a second control logic. The first control logic is selected to be suitable for active mode. The second control logic is selected to be suitable for standby mode.

[0039] In some embodiments, the first control logic and the second control logic are pre-selected or predetermined and are set in one of the corresponding engine control logics 306, 308. The operation mode selector 304 can selectively connect the engine control logics 306, 308 to the engines 102, 104 according to the operation mode of each corresponding engine 102, 104.

[0040] In some embodiments, engine control logics 306 and 308 are configured to select a suitable control logic from two or more available control logics upon receiving a signal from the operation mode selector 304 indicating the operation mode of the respective engine 102 or 104. Engine control logic 306 is associated with engine 102 and selects a suitable control logic for engine 102 based on the signal indicating the operation mode of engine 102 received from the operation mode selector 304. Engine control logic 308 is associated with engine 104 and selects a suitable control logic for engine 104 based on the signal indicating the operation mode of engine 104 received from the operation mode selector 304.

[0041] What will be understood is that Figure 3 The embodiment described is merely one example of the construction of controller 210. For example, the operating mode selector 304 may also respond to other inputs to trigger different control logics for engines 102, 104, such as engine operating parameters, aircraft operating parameters, emergency signals, etc. Furthermore, engine control logics 306, 308 may be provided in separate embodiments of controller 210, whereby each engine 102, 104 has its own controller 210, which can control according to more than one control logic depending on the operating mode of the respective engine 102, 104.

[0042] Go to Figure 4A The illustration shows an exemplary embodiment of engine control logic 306 for a first engine 102 operating in an active mode. As described herein, the active mode enables engine 102 to provide power to the aircraft. Control loop 402 adjusts the fuel flow rate (W) based on the error 404 between actual target parameter 406 and nominal target parameter 408. f The actual target parameter 406 can be measured, synthesized, or simulated in real time. The target parameter can be the gas generator speed (Ng), low-pressure rotor speed (Np), high-pressure rotor speed (Nh), or any other engine parameter that the main engine control can be based on. The control loop 402 also adjusts the VGM position based on the VGM schedule 410. The control logic 306 applied to activate engine 102 may differ from... Figure 4A The example shown. For example, open-loop control based on fuel flow or other closed-loop control can also be used.

[0043] Figure 4BAn exemplary embodiment of engine control logic 308 for a second engine 104 operating in standby mode is illustrated. As described herein, standby mode causes engine 104 to essentially not provide power to the aircraft. Control loop 412 adjusts the fuel flow rate (W) based on an error 414 between the actual engine compressor speed 416 and the adjusted target engine compressor speed 418. f The actual target engine compressor speed 416 can be measured, synthesized, or simulated in real time. Control loop 412 also adjusts the VGM position based on a trimmed VGM plan 420 for the corresponding compressor speed. As used herein, the terms "trimmed," "trimmed," and "trimmed" refer to adjustments or deviations applied to nominal or original values. In some embodiments, the trimming is applied directly to the nominal target parameter or plan, and only the trimmed target parameter or trimmed plan is used in engine control logic 308. In some embodiments, the nominal target parameter or plan is provided to engine control logic 308, and the trimming is applied within control logic 308. In both embodiments, control loop 412 bases its adjustments to fuel flow and VGM position on trimmed values, rather than on nominal values.

[0044] When operating in standby mode, target parameters for trimming are determined to optimize one or more parameters of engine 104. In some embodiments, the optimized parameter is fuel consumption, such that a fuel consumption target specific to engine 104 operating in standby mode can be used to find a trimmed value for a target compressor speed of engine 104. In some embodiments, the trimmed value is associated with a specific engine and varies from engine to engine; that is, the trimmed value is associated with the engine serial number. In some embodiments, the trimmed value is associated with an engine model, and the same trimmed value can be applied to all engines of a given model. In some embodiments, the trimmed value is associated with engines of a given engine model that share one or more common characteristics, such as degradation index or efficiency level. Other criteria may also be applied to associate the trimmed value with one or more engines.

[0045] In some embodiments, the optimized parameters are compressor stall margin, compressor surge margin, compressor flameout margin, or any other suitable engine parameter. In some embodiments, the trim value is set to optimize multiple parameters, such as fuel flow rate and pressure ratio, or stall margin and inlet temperature. Optimization of three or more parameters may also be performed.

[0046] In some embodiments, a multivariate approach is used to optimize one or more parameters. In practice, trimming only one engine parameter, such as compressor speed, may allow optimization of a given parameter, such as fuel flow, but may cause another parameter, such as pressure ratio, to no longer meet the requirements. Therefore, trimming is performed simultaneously on multiple engine parameters, such as compressor speed and VGM, to meet the desired criteria and optimize at least one parameter.

[0047] Figure 5A The diagram illustrates an example showing the relationship between a target parameter (y-axis) and compressor speed (x-axis). Curve 500 plots a set of nominal values ​​for compressor speed as a function of the target parameter, which could be, for example, fuel flow rate. In this example, the nominal compressor speed is S1 for the target parameter of TP1. Applying trimming 504 to the nominal compressor speed 500 shifts the compressor speed to curve 502, which corresponds to the trimmed compressor speed value. For the same target parameter of TP1, the trimmed compressor speed is S2.

[0048] Figure 5B A similar trimming example applied to VGM planning is illustrated. Curve 510 illustrates the nominal VGM planning as a function of engine compressor speed. For compressor speed S3, the nominal VGM position is set to POS1. Applying trimming 514 to nominal VGM planning 510 shifts the VGM position to curve 512, which corresponds to the trimmed VGM planning. For the same compressor speed S3, the trimmed VGM position is POS2.

[0049] Figure 5C The diagram illustrates the effect of combining trims 504 and 514, applying trims to Ng and VGM. Curve 520 represents the nominal target compressor speed with a nominal VGM plan. Applying trim 524 shifts the compressor speed value to curve 522, which represents the trimmed compressor speed with a trimmed VGM plan. Applying trim to the compressor speed only shifts point 526 along curve 520 to point 528. Applying trim to the VGM position only shifts point 526 to point 530 on curve 522. Applying trim 524 to both the compressor speed and VGM plan achieves the target parameter TP2 at point 532 while allowing other engine requirements (or standards) to be met. This multivariate approach allows control logic 308 to be customized for engine 104 when engine 104 is operating in standby mode, enabling one or more engine parameters to be optimized using two or more control variables.

[0050] In some embodiments, these trims are determined during the production of engine 104 while the engine is running in the test unit. Trim values ​​may be uploaded to controller 210 and / or to engine control logic 308. Trim values ​​may also be determined offline or via controller 210 through engine simulation and / or modeling. Trim values ​​may be scaled as a function of one or more parameters such as altitude and outside air temperature to determine the target compressor speed for the final trim and / or the VGM planning for the trim. Scaling may be performed by control logic 308 based on a specific operating point in the envelope at a given time point.

[0051] In some embodiments, the controller 210 is implemented as a system 601 in one or more computing devices 600, the system 601 being used to operate an aircraft having two or more engines, such as... Figure 6 As shown in the diagram. For simplicity, only one computing device 600 is shown, but system 601 may include more computing devices 600 operable to exchange data. For example, each engine control logic 306, 308 may be implemented in a separate computing device 600. The computing devices 600 may be the same or different types of devices. Note that system 601 may be implemented as part of a Full Authority Digital Engine Control (FADEC) or other similar device, including Electronic Engine Control (EEC), Engine Control Unit (ECU), Electro-Propeller Control, Propeller Control Unit, etc. Other embodiments may also be applicable.

[0052] The computing device 600 includes a processing unit 602 and a memory 604 in which computer-executable instructions 606 are stored. The processing unit 602 may include any suitable means configured to implement a method such that the instructions 606, when executed by the computing device 600 or other programmable device, cause a function / action / step to be performed. For example, the processing unit 602 may include any type of general-purpose microprocessor or microcontroller, digital signal processing (DSP) processor, central processing unit (CPU), integrated circuit, field-programmable gate array (FPGA), reconfigurable processor, other suitablely programmable or programmable logic circuitry, or any combination thereof.

[0053] Memory 604 may include any suitable known or other machine-readable storage medium. Memory 604 may include non-transitory computer-readable storage media, such as, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or apparatuses, or any suitable combination thereof. Memory 604 may include any suitable combination of computer memories, whether internal or external to the device, such as random access memory (RAM), read-only memory (ROM), optical disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferroelectric RAM (FRAM), etc. Memory 604 may include any storage device (e.g., apparatus) suitable for retrievably storing machine-readable instructions 606 executable by processing unit 602.

[0054] refer to Figure 7 The illustration depicts an exemplary method 700, executed via system 601, for operating an aircraft having two or more engines. At step 702, the two or more engines operate with an asymmetric operating mechanism. Thus, the first engine is in an active mode to power the aircraft, while the second engine is in a standby mode to substantially not power the aircraft.

[0055] At step 704, a first control logic is used to control the first engine. This first control logic can be an open-loop or closed-loop control logic. The first control logic can be based on fuel flow rate, Ng, Nh, Np, or any other engine parameters.

[0056] At step 706, a second control logic is used to control the second engine. This second control logic is a closed-loop control logic based on compressor speed and VGM settings. The nominal target compressor speed and nominal VGM settings are adjusted using trimmed values ​​that depend on at least one parameter of the second engine in standby mode. This at least one parameter can be one or more of fuel consumption, stall margin, shutdown margin, and any other parameter that differs when the engine operates in standby mode compared to normal or active power mode operation. The VGM setting can be used with variable inlet guide vanes, a bleed-off valve, or any other mechanism of the engine with a variable position, for which changing the position causes a change in engine operation.

[0057] In some embodiments, the trim value is determined during the engine production phase and uploaded to the computing device 600 for use with the second control logic. In some embodiments, the trim value is determined by the computing device 600. In some embodiments, the computing device 600 and / or the control logic retrieve the trim value from a storage medium as needed. In some embodiments, the target compressor speed and VGM settings provided to the second control logic have been adjusted using the trim value.

[0058] It will be understood that this disclosure also teaches a method for operating a gas turbine engine in a given operating mode, whereby the engine operates within a power range having thermodynamic / aerodynamic characteristics. These thermodynamic / aerodynamic characteristics are addressed by using adjusted values ​​for a target compressor speed and VGM, which depend on at least one parameter of the engine when it is in the given operating mode. Engine control logic applied in the operating mode determines the error between the adjusted target compressor speed and the actual compressor speed, and adjusts the fuel flow to the engine based on this error when the engine is in the given operating mode, such as... Figure 4B As shown in the exemplary control logic.

[0059] The methods and systems described herein may be implemented in high-level procedural or object-oriented programming or scripting languages, or combinations thereof, to communicate with or assist the operation of a computer system, such as computing device 600. Alternatively, these methods and systems may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing these methods and systems may be stored on a storage medium or device, such as ROM, disk, optical disk, flash drive, or any other suitable storage medium or device. This program code may be read by a general-purpose or special-purpose programmable computer for constructing and operating the computer, when the storage medium or device is read by the computer, to execute the programs described herein. Embodiments of these methods and systems may also be considered to be implemented by means of a non-transitory computer-readable storage medium on which a computer program is stored. This computer program may include computer-readable instructions that cause the computer, or more specifically, the processing unit 602 of computing device 600, to operate in a particular and predefined manner to perform the functions described herein, such as those described in method 700.

[0060] Computer-executable instructions can take many forms, including program modules, which are executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. Typically, in various embodiments, the functionality of program modules can be combined or allocated as needed.

[0061] The embodiments described herein provide useful physical machines and specially constructed computer hardware arrangements. The embodiments described herein relate to electronic machines and methods implemented by electronic machines, suitable for processing and converting electromagnetic signals representing various types of information. The embodiments described herein generally and holistically relate to machines and their uses; and the embodiments described herein have no meaningful or practical applicability outside their use with computer hardware, machines, and various hardware components. Replacing the specially constructed physical hardware that performs various actions with, for example, mental steps may significantly affect how the embodiments work. Such computer hardware limitations are clearly fundamental elements of the embodiments described herein, and they cannot be omitted or replaced by mental means without having a substantial impact on the operation and structure of the embodiments described herein. Computer hardware is essential for implementing the various embodiments described herein and is not only used for performing steps in a fast and efficient manner.

[0062] The term “connected” or “coupled to” can include both direct coupling (where two elements coupled to each other are in contact with each other) and indirect coupling (where at least one additional element is located between the two elements).

[0063] The technical solutions of the embodiments may be in the form of a software product. This software product may be stored in a non-volatile or non-transitory storage medium, such as an optical disc read-only memory (CD-ROM), a USB flash drive, or a removable hard drive. The software product includes multiple instructions that enable a computer device (personal computer, server, or network device) to execute the methods provided in the embodiments.

[0064] The embodiments described herein provide non-limiting examples of possible implementations of the present technology. Upon review of this disclosure, those skilled in the art will recognize that changes can be made to the embodiments described herein without departing from the scope of the present technology. For example, trim values ​​can be applied simultaneously to compressor speed, VGM settings, and one or more additional parameters to optimize engine operation in standby mode. The engine can be a turbofan engine or a turboshaft engine, rather than a turboprop engine. The engine can have a single tube shaft instead of multiple tube shafts. Given this disclosure, those skilled in the art can make further modifications that will fall within the scope of the present technology.

Claims

1. A method for operating an aircraft having two or more engines, the method comprising: The two or more engines of the aircraft are operated using an asymmetric operating mechanism, wherein a first engine of the aircraft is in an active mode to provide power to the aircraft, and a second engine of the aircraft is in a standby mode to substantially not provide power to the aircraft. The first control logic is used to control the first engine in the activation mode; and The second engine in the standby mode is controlled using a second control logic different from the first control logic. The second control logic is based on a trimmed target compressor speed and a trimmed variable geometry (VGM) setting. The trimmed target compressor speed includes a nominal target compressor speed adjusted using a first engine-specific trim value, and the trimmed VGM setting includes a nominal VGM setting adjusted using a second engine-specific trim value. The first engine-specific trim value and the second engine-specific trim value are specific to the second engine and depend on at least one parameter including the fuel consumption of the second engine in the standby mode.

2. The method according to claim 1, wherein, The first engine-specific trim value and the second engine-specific trim value are determined during the production phase of the second engine.

3. The method according to claim 1, wherein, The at least one parameter of the second engine in the standby mode includes at least one of surge margin and shutdown margin.

4. The method according to claim 1, wherein, The VGM is configured for at least one of the vent valve and variable inlet guide vanes of the second engine.

5. The method according to claim 1, wherein, The second control logic includes a control loop, the control loop being configured to: The error between the actual compressor speed of the second engine and the adjusted target compressor speed is received as a first input; Receive the modified VGM settings as a second input; And the first input and the second input are used to adjust the fuel flow and VGM of the second engine.

6. A method for operating a gas turbine engine, the method comprising: Obtain a target compressor speed and variable geometry (VGM) setting adjusted using trim values, which depend on at least one parameter of the engine operating in a given operating mode; Determine the error between the adjusted target compressor speed and the actual compressor speed of the engine; as well as When the engine is in the given operating mode, the fuel flow rate to the engine is adjusted based on the error; The gas turbine engine is part of an aircraft having two or more engines operating with an asymmetric operating mechanism, wherein a first engine of the two or more engines is in an active mode to power the aircraft, and a second engine of the two or more engines is in a standby mode to substantially not power the aircraft, and wherein the first engine is controlled using a first control logic, and the second engine is controlled using a second control logic different from the first control logic, the second control logic being based on a trimmed target compressor speed and a trimmed variable geometry (VGM) setting, the trimmed target compressor speed including a nominal target compressor speed adjusted using a first engine-specific trim value, the trimmed VGM setting including a nominal VGM setting adjusted using a second engine-specific trim value, the first engine-specific trim value and the second engine-specific trim value being specific to the second engine and dependent on at least one parameter including the fuel consumption of the second engine in the standby mode.

7. The method according to claim 6, wherein, The first engine-specific trim value and the second engine-specific trim value are determined during the engine's production phase.

8. The method according to claim 6, wherein, The at least one parameter includes at least one of surge margin and shutdown margin.

9. The method according to claim 6, wherein, The given operating mode is a standby mode that essentially does not provide power to the aircraft.

10. A system for operating an aircraft having two or more engines, the system comprising: At least one processing unit; as well as A non-transitory computer-readable medium having program code stored thereon, the program code being executable by the at least one processing unit to: The two or more engines of the aircraft are operated using an asymmetric operating mechanism, wherein a first engine of the aircraft is in an active mode to provide power to the aircraft, and a second engine of the aircraft is in a standby mode to substantially not provide power to the aircraft. The first control logic is used to control the first engine in the activation mode; and The second engine in the standby mode is controlled using a second control logic different from the first control logic. The second control logic is based on a trimmed target compressor speed and a trimmed variable geometry (VGM) setting. The trimmed target compressor speed includes a nominal target compressor speed adjusted using a first engine-specific trim value, and the trimmed VGM setting includes a nominal VGM setting adjusted using a second engine-specific trim value. The first engine-specific trim value and the second engine-specific trim value are specific to the second engine and depend on at least one parameter including the fuel consumption of the second engine in the standby mode.

11. The system according to claim 10, wherein, The first engine-specific trim value and the second engine-specific trim value are determined during the production phase of the second engine.

12. The system according to claim 10, wherein, The at least one parameter of the second engine in the standby mode includes at least one of surge margin and shutdown margin.

13. The system according to claim 10, wherein, The VGM is configured for at least one of the vent valve and variable inlet guide vanes of the second engine.

14. The system according to claim 10, wherein, The second control logic includes a control loop, the control loop being configured to: The error between the actual compressor speed of the second engine and the target compressor speed after adjustment is received as a first input; Receive the modified VGM settings as a second input; And the first input and the second input are used to adjust the fuel flow and VGM of the second engine.

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